How many times have you not done something you wanted to do becuase you couldn't find someone to go with? It is fairly common to just stay home instead of venturing out solo.
The first time you do something that typically involves couples or groups can be scary. Even going to a restaurant for dinner alone can invite sideways glances from others.
Being alone can encourage negative thinking to fill your energy and bring you down. The great thing about being with others is that their voices can drown out the feelings of imposter syndrome and poor self worth.
Realizing that safety concerns are a very real issue for people, there are numerous options to enjoy activities safely. These include small alarms with lights, ensuring your cell phone is charged, informing friends and family of your plans, and others. Personally, I utilize a combination of all of these, when I am solo running/hiking in remote areas I snap pics of trail signs and text to my partner the time I was at this sign and which way I am headed since the text can take minutes to process. I also have an alarm and carry extra water and snacks. That is the easy task.
The much more challenging task is to rid yourself of the negative thoughts. At times the negativity can make normally enjoyable activities unbearable. Options to alleviate this can be music, audiobooks, and other techniques to increase positive thinking.
Going solo can be intimidating and scary, but also a great opportunity to enjoy and discover new things.